5th July 2019

How autonomous, electric and shared mobility vehicles plus IoT connectivity are shaping tyre development

One aspect of tyres will never change, even if affordable flying vehicles do become a reality. Tyres will always remain vitally important, as they are the only parts of a car, van or larger vehicle that directly contact the road. As TyreSafe, the UK charity dedicated to raising awareness of tyre safety, explains1: “safety in acceleration, braking, steering and cornering all depend on a relatively small area of road contact.” That’s a significantly humbling thought, but however important some motorists do perceive tyres, they have long been regarded by most as relatively uninteresting black rubber circles.

Perhaps the most interesting development pertaining to a product that can never change its essential circular shape was the introduction of run-flat tyres, the first iterations attributed to Michelin in the 1930s in the context of military vehicles, which is entirely logical due to the need to keep them and their personnel and cargoes moving in times of conflict or emergency. AutoExpress describes2 how these tyres incorporated a partly-bulletproof lining made of foam, which was able to support a vehicle’s weight should the tyre lose inflation. In the 1950s, Chrysler and Goodyear collaboratively trialled their own tyre with a weight-bearing internal lining, but it proved unfeasibly expensive just like Michelin’s, albeit in the consumer segment.

Remaining relatively niche in current times and associated primarily with BMW models, run-flat technology could excusably now be viewed as unremarkable, but with the proliferation of ‘connected’ products, systems, infrastructure and vehicles, the latest tyre advancements are nothing short of fascinating.

The challenges EVs pose to tyre manufacturers

Fleet News is right in saying that connected, autonomous and electric vehicle technologies ‘will not only change the cars we use, but also transform how we use them”3 and, as Continental’s development head Phillip Struck told the publication, ‘all these concepts still rely on tyres and rims.’

Although the increasing number of cars introduced that are capable of levels 3 and 4 in autonomy doesn’t mandate any particularly radical tyre requirements, electric vehicles are presenting manufacturers with a challenge because of the weight of their batteries and the effect that the instantaneous maximum torque of electric power has on their tyres. Continental reports increased tyre wear for EVs as anywhere between 5% and 35%, the higher figure seeming fairly concerning to us.

With internal and external quietness, CO2 emissions, electric range and traction in mind, other tyre producers including Goodyear are also being required to adapt and develop low-rolling-resistance tyres specifically aimed at EVs, which often feature taller, narrower designs, plus lower speed ratings.

The fully-electric Audi e-tron SUV, for example, is fitted with Goodyear Eagle F1 Asymmetric 3 SUV tyres, reportedly4 because of the tyre’s ability to negate the 25% increase in wear that the EV’s higher torque results in. The brand’s SoundComfort Technology also keeps the e-tron as quiet as possible, and the tyre’s SUV focus improves the braking distance by 4ft in both the dry and wet.

Connected autonomous vehicles and punctures

Until affordable flying vehicles perhaps do actually become a reality, which we can’t envisage happening on any significant scale for at least decades, autonomous or ‘driverless’ cars, vans and larger vehicles will always use tyres and will therefore remain exposed to punctures, blowouts and general tread depth wear.

Without any human control or even attention other than cursory interest from the passengers they transport, connected autonomous vehicles (CAV) will need to be able to monitor themselves while travelling around and also before departing and on returning to their fixed or free-floating parking locations.

Relatively simplistic tyre pressure monitoring systems, in both passive and more advanced active form, have of course been in existence for over twenty years in mainstream cars, but they unsurprisingly only monitor pressure rather than wear. Another disadvantage of traditional TPMS is that they react relatively slowly to punctures, motorway driving at high speeds sometimes prolonging any warning because of the way in which frictional heat keeps tyre pressure elevated.

For CAV operators, the ability for vehicles to monitor their own tyres’ condition will be a significant efficiency and safety boost, and the pioneering strides made by the world’s leading tyre manufacturers are remarkable.

Continental’s sensor-rich, shape-morphing tyres

The Irish Times4b sums up the near future of the tyre nicely by stating that “the rubber on the road is about to get a lot more sophisticated” as “Continental showcases [a] concept tyre featuring tiny sensors that inform [the] car of [the] tyre’s health”.

We agree that in today’s world where all manner of things are increasingly becoming connected to the Internet of Things (IoT) via 4G and 5G and the benefits of artificial intelligence (AI) are bestowed upon so many products and services, the arrival of the ‘smart tyre’ was inevitable.

By embedding minute sensors in the ContiSense tyre’s carcass, drivers physically sat inside a vehicle and even fleet managers or other authorised ‘remote’ individuals will be informed of events like punctures, tyre damage and unusual heat or pressure build-up in real-time. Such alerts will undoubtedly aid company car drivers, private and commercial motorists in getting one or more tyres changed before a potentially dangerous blowout occurs, therefore reducing the safety risk for them and other road users. Predictive or at least expedient tyre replacement or ‘plugging’ will also bring time and cost benefits by reducing unexpected vehicle downtime, missed meetings, appointments, flights and other lamentable results that affect many of today’s drivers.

The entire tyre behaving like an electrical circuit is an exciting prospect and Continental’s usual pioneering approach is evident in the conductive filler compound used for two of the tyre’s layers, while the third layer is designed as an isolator.

Continental ContiAdapt tyre

Continental’s perhaps even more remarkable concept, though, is called ContiAdapt, and has been devised to meet the need created by CAVs and EVs for tall, skinny tyres on large diameter wheels such as 20” or 21” alloy rims. ContiAdapt tyres have been created to be “all tyres to all cars” and can physically change shape to meet dynamic vehicle requirements, morphing in size and form at the click of a button, inflating for cars and vans with wider rims while deflating for those with narrower wheels. Fascinatingly, ContiAdapt also involves actual alloy wheels themselves changing size along with the tyres surrounding them, enabling 4×4-equipped vehicles of the near future to switch to wider wheels shod with tyres of lower pressure ready for driving on off-road terrain, before reverting back to narrower tyres pumped to higher pressures for on-road driving at high speeds, all while retaining the same overall diameter within the vehicle’s wheel arches.

Goodyear envisages tyres as spherical and magnetically suspended

The Eagle-360 tyre concept unveiled5 at the Geneva Motor Show in 2016 demonstrated significant foresight and will quite possibly have made other firms and individuals ponder why the notion of replacing tyres with spheres hadn’t been mooted before on any scale. While four-wheel steering and other innovations have been introduced on certain models from different OEMs, it’s uncannily obvious that spherical ‘tyres’ would indeed provide ultimate manoeuvrability and safety and, as Goodyear also identifies, enable car parks to increase their capacities by reducing the size of bays. Goodyear’s Eagle-360 concept tyres aren’t even physically connected to the vehicle but are instead suspended by magnetic levitation, essentially allowing their shape to morph to overcome obstacles without necessitating directional change, and for the ride to be remarkably smooth.

Goodyear Eagle-360 tyre

Goodyear also introduced its own connectivity to the world of tyre design, with sensors embedded inside the Eagle-360 monitoring road, weather, surface and other conditions and communicating this data to the car while self-regulating the spherical tyre’s wear to extend the vehicle’s mileage.

Biomimicry, algorithms and AI to improve road safety

Optimising the tyre’s tread and other characteristics to suit different markets was also highlighted as a possibility thanks to its production via 3D printing, and Goodyear was keen to describe how it uses biomimicry to translate the intelligence of nature into its products, the tread pattern mimicking brain coral and the groove bottom mirroring elements of sea sponges, for example, to reduce potential aquaplaning.

The company also presented its IntelliGrip vision6 specifically designed for CAVs and their data-intense control systems, which we certainly agree is a crucial step as tyres will be such vehicles’ primary links to the road more than ever before. Algorithms were developed to enhance the monitoring of tyre condition and to prolong their wear, while sensors detecting rain or slippery road surfaces for any other reasons would automatically limit equipped vehicles’ speed, which we would welcome from a road safety perspective.

A year later, an ‘Urban’ version of the Eagle-360 tyre concept was showcased7, with artificial intelligence (AI) at its core and, in Goodyear’s view, perfectly timed because “a revolution will take place at the intersection of autonomy, mobility and connectivity”. With a super-elastic polymer bionic skin along with tread that automatically morphs, the Eagle 360 Urban was pitched at becoming part of a CAV’s ‘nervous system’, connected to the Internet of Things (IoT) and designed to act as the brain, learning, thinking and continuously adapting to the environment and a plethora of other variables. ‘Dimples’ sprout out and embedded actuators change individual sections of the tyre’s tread to provide extra traction in wet or loose conditions, while the skin acts in a self-healing way and physically rotates to negate any punctures or other damage, maximising uptime for fleets and MaaS operators. An Urban iteration of Goodyear’s IntelliGrip tyre concept was also unveiled8, promoted as a predictive maintenance solution for future fleets, complete with a tall, narrow shape to increase EVs’ battery ranges.

Electric Drive Technology9 that Goodyear presented in 2018 involved thinner ‘sipes’ or channels in the tyres’ tread to maximise the area of rubber in contact with the road, along with cavity shapes designed for higher load-carrying to compensate for the weight of EV batteries, plus sidewalls and materials engineered for minimal aerodynamic drag and energy consumption.

As car-sharing and other MaaS concepts continue to grow in popularity, we feel that it’s right for tyre manufacturers to be designing tyres with shared mobility fleet operators in mind10 to account for each vehicle being expected to cover higher mileages than many currently do.

But if flying vehicles do materialise?

This year’s concept from Goodyear is perhaps even more incredible, futuristic and in some ways perhaps optimistic. AERO is a ‘multimodal tilt-rotor two-in-one’ concept aimed at autonomous vehicles of the future, capable of both road and air use. Airless and comprised of spokes rather than a conventional tyre’s pneumatic structure, AERO tyres would be able to support the vehicle’s weight on the ground or tilt, rotate and provide lift when airborne, with magnetic propulsion to remove any friction. Light-based fibre-optic sensors will monitor road condition, and artificial intelligence will even equip vehicles fitted with these revolutionary tyres to automatically switch from road to air based on conditions and other data.

Hankook demonstrates environmentally-friendly tyre materials for EVs

In the Wired article11 ‘Hankook’s new tire uses tree resin to keep electric cars rolling’, the way in which tyres will play a key role in eking out the longest battery ranges possible and making EVs as quite as they can be was once again highlighted.

Hankook has developed an EV-specific tyre called the Kinergy AS EV, which reinforces the firm’s environmental aims by incorporating a substance called Aqua Pine – vegetable oil resin extracted from conifer trees, which enhances a tyre’s handling, braking, grip and performance, particularly on wet surfaces, by means of the harder resultant compound. The strong heat resistance properties of the other materials used throughout the tyre make it more hard-wearing and able to retain its shape and structural integrity for longer, including a belt made from Aramid hybrid synthetic polymer, which distributes pressure more evenly. The South Korean tyre brand’s fastidious design endeavours also include sidewalls and tread patterns that reduce certain frequencies during driving, lessening both cabin and exterior noise.

Hankook EV tyres

Showcased alongside another concept labelled the Aeroflex, produced for the motorsport world, Hankook’s Hexonic tyre designed for self-driving cars sees its tread separated into a series of hexagonal modules that intelligently group or split in real-time to channel water through more efficiently12. The hexagons each incorporate an internal Y-shape to enhance smoothness and grip even further and are fed information by seven sensors, the ultimate aim of the Hexonic being to make the ride of autonomous shared mobility vehicles as comfortable as possible13. This makes sense to us, as traditional characteristics sought by car-testers such as ‘road feedback’ and ‘steering feel’ will no longer be relevant.

Hankook Kinergy AS EV tyre

Michelin’s airless tyre aims to make punctures irrelevant

The Wired piece additionally revealed that Tesla, one of electric cars’ chief pioneers, and also Chevrolet, have been extensively utilising Michelin’s test-track in California. The latter OEM’s most prominent forays into electrification so far have included the Volt, which was the Vauxhall Ampera plugin hybrid’s sister model, and the smaller Bolt, a full EV.

Focussing on Michelin, though, and the firm’s latest concept makes run-flat tyres’ advantage of enabling equipped vehicles to continue to be driven at reduced speeds for short distances before being imminently replaced seem antiquated. Describing a tyre as puncture-free or ‘proof’ is one thing, but conceptualising a tyre that doesn’t use any air is another and is really quite remarkable in our view, especially from one of the world’s foremost producers. It came as something of a surprise that the French tyre-maker first envisaged a tyre without air in 2005, with its X TWEEL airless radial tyre technology14, and subsequently revealed a $50 million plant for production of what it sees as the future of tyres.

Collaborating with GM, Michelin’s latest airless tyre, aimed at EVs in particular, will be called the Uptis, and has so far reportedly attracted interest from fleets, shared mobility and rental companies in the main, with the expectation that it will initially prove too expensive for private motorists15. The Uptis is predominantly made of rubber, much like traditional tyres, but will also incorporate aluminium plus a unique resin-embedded fiberglass-reinforced material16. It will weigh a few pounds more than a typical tyre but will actually be slightly lighter than a run-flat tyre.

Airless tyre - Michelin Uptis (similar to X TWEEL)

Michelin says that the tyre won’t feel any different to conventional air-filled tyres from the perspective of drivers and passengers, and the benefits are wide-ranging, from its construction requiring far less raw materials and energy, while few if any Uptis tyres will become damaged and require premature disposal, and roads will be safer with punctures eliminated. According to Michelin, around 20% of the world’s 200 million tyres are rendered unusable because of punctures or irregular wear due to poor geometry and other factors.

We can see the advent of airless tyres bringing significant benefits to fleets in terms of increased vehicle uptime, much-reduced maintenance, added reassurance over the safety of their drivers, and of course reduced tyre spend. Vehicles fitted with Uptis tyres won’t need a spare carrying on-board, or indeed a jack or even a TPMS. We can also see shared CAV mobility providers identifying the benefits of such airless tyres, and it’s fair to say that they will surely become a reality ahead of even more radical concepts such as Goodyear’s Oxygene tyre that incorporates living moss in its structure. It’s something of a shame that Uptis won’t reportedly start being fitted to production vehicles until 2024, but it’s encouraging that it’s already being tested on Chevy Bolt EVs in the meantime. Toyota did debut its own airless tyre, developed with Sumitomo Rubber, at the Tokyo Motor Show in 2017 – but it looks like the French will make it a reality sooner.

Bridgestone tyres optimised for urban EVs

Intriguingly, the website of “the world’s largest tyre and rubber company”, Bridgestone, openly states its changed market positioning and intentions by saying “Bridgestone EMEA is evolving from premium tyre producer to leader in mobility solutions”, and SEAT has chosen the brand’s ‘ologic’ technology for its electric concept car, Minimó.

A two-seater EV equipped with 5G technology, its battery can be replaced in just seconds and offers slightly over 100km per charge, making Minimó’s urban city market evident17. The car’s tall, narrow tyres have been specially developed for SEAT at Bridgestone’s R&D Centre in Rome and are, according to the tyre producer, optimised for micro-mobility and Connected Autonomous Shared Electric (CASE) vehicles.

Bridgestone’s ologic technology18, which very much has EVs and shared mobility vehicles in mind and particularly those primarily aimed at cities and towns, is founded on the principles of narrow, large-diameter tyres inflated to higher than typical pressures, their shape mitigating deformation, boosting fuel economy and reducing aerodynamic resistance.

It’s fascinating to discover how significant technological advancements like these are being made in relation to individual vehicle parts, at a time when the electric and autonomous vehicles they will be fitted to dominate most media coverage. We welcome such innovative strides which will clearly not only bring financial and efficiency benefits but, importantly, road safety and environmental improvements too.

 

Sources:
1. https://www.tyresafe.org/wp-content/uploads/2019/05/TS-Car-Tyres-A5-leaflet-PRINT-compressed.pdf
2. https://www.autoexpress.co.uk/car-news/98109/what-are-run-flat-tyres
3. https://www.fleetnews.co.uk/fleet-management/tyre-management/making-tyres-smart
4. https://www.tirereview.com/goodyear-eagle-f1-asymmetric-3-suv-to-be-oe-on-audi-e-tron/
4b. https://www.irishtimes.com/life-and-style/motors/smart-tyres-the-rubber-on-the-road-is-about-to-get-a-lot-more-sophisticated-1.3895816
5. https://news.goodyear.eu/goodyear-unveils-eagle-360-a-visionary-tire-concept-for-future-autonomous-vehicles/
6. https://news.goodyear.eu/goodyear-showcases-concept-tire-with-advanced-sensor-technology-for-early-generation-autonomous-vehicles/
7. https://news.goodyear.eu/goodyear-unveils-the-eagle-360-urban-a-concept-tire-powered-by-artificial-intelligence/
8. https://news.goodyear.eu/goodyear-introduces-the-intelligrip-urban-concept-a-smart-tire-for-future-urban-fleets/
9. https://news.goodyear.eu/goodyear-presents-new-tire-technology-designed-to-advance-the-performance-of-electric-vehicles/
10. https://news.goodyear.eu/goodyear-demonstrates-its-intelligent-tire-prototype-on-the-road/
11. https://www.wired.com/story/hankook-ev-electric-car-kinergy-tire/
12. https://newatlas.com/hankook-concept-tires-hexonic-aeroflow/57508/
13. https://www.hankooktire-mediacenter.com/index.php?id=151&flt=1&tx_news_pi1%5Bnews%5D=5147&tx_news_pi1%5Bcontroller%5D=News&tx_news_pi1%5Baction%5D=detail&cHash=d70ddc280326c45be24b187063d3f51f
14. https://www.nytimes.com/2005/01/03/automobiles/reinventing-the-wheel-and-the-tire-too.html
15. https://interestingengineering.com/puncture-proof-tires-revealed-by-gm-and-michelin
16. https://www.greencarreports.com/news/1123423_no-puncture-no-pressure-gm-could-offer-airless-michelin-tire-in-2024-ev
17. https://www.bridgestonenewsroom.eu/brandportal/bridgestonepr/default/news-detail/671?lang=eu
18. https://www.bridgestone.com/technology_innovation/ologic/